Sandstone
Arenicola (comprising mostly Quartz, SiO2)
sedimentary
Category
Organic Gemstone (Often Associated With Sedimentary Sequences)
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (primarily SiO₂)
sedimentary
Turquoise and Hematite
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Hematite (Fe2O3)
mineral
Granite
Granite (a felsic intrusive igneous rock composed primarily of quartz, feldspar, and mica)
igneous
Chert (Black Chert/Flint)
Silicon Dioxide (SiO2)
sedimentary
Quartz Vein (Iron-stained)
Silicon Dioxide (SiO2) with limonite/hematite staining
mineral
Peridot
Olivine (Magnesium Iron Silicate), (Mg, Fe)2SiO4
mineral
Porphyritic Basalt (Chinese Writing Stone)
Porphyritic Basalt with Feldspar Phenocrysts
igneous
Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende, chlorite, or manganese/iron oxides
mineral
Banded Chert
Cryptocrystalline Quartz (SiO2)
sedimentary
Unakite
Epidotized Granite (composition: K-feldspar, Epidote, and Quartz)
metamorphic
Rhodonite
Manganese Inosilicate (MnSiO3), often with Ca, Fe, Mg, Zn
Mineral
Emerald in Matrix
Beryl (Be3Al2Si6O18) with trace amounts of Chromium/Vanadium
mineral
Emerald in Host Rock
Beryl (Be3Al2Si6O18) containing Chromium and/or Vanadium
mineral
Quartz
Quartz (SiO₂)
mineral
Chrysanthemum Stone
Celestine (SrSO4) or Calcite (CaCO3) in Limestone/Porphyry matrix
metamorphic
Chalcedony (Botryoidal)
Silicon Dioxide (SiO2)
mineral
Dendritic Agate / Moss Agate
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
mineral
Rose Quartz
Rose Quartz (SiO₂)
Mineral
Fossiliferous Limestone with Rugose Coral
Calcium Carbonate (CaCO3) featuring Rugosa (extinct order of solitary and colony corals)
sedimentary
Chalcedony
Chalcedony (a microcrystalline variety of Quartz, SiO2)
Mineral
Chert (Yellow or Tan variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
Metamorphic Rock (variety of Quartz)
Pumice
Pumicite (Amorphous glass with varying chemical composition, often rhyolitic)
Igneous
Opal
Hydrous silicon dioxide (SiO2·nH2O)
mineral
Shale (Beach-worn)
Laminated Pelite (primarily clay minerals and quartz)
sedimentary
Chert (often called Jasper or Flint in this color variety)
Silicon Dioxide (SiO2)
sedimentary
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2
Mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
sedimentary
Coquina Limestone (Fossiliferous Limestone)
Calcareous bioclastic sedimentary rock (CaCO3)
sedimentary
Chert (varieties: Flint or Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified wood (SiO2 - Silicon Dioxide)
sedimentary
Chert (Gravel specimen)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary